Types of aggregates on the basis of grain size & volume weight

Aggregates alias construction aggregates are made of materials like sand, gravel, crushed stone, slag and recycled concrete. The standard types of aggregates are granite aggregates, gravel aggregates, limestone aggregates, secondary aggregates and slag aggregates. The aggregates are obtainable in different sizes like 10 mm, 20 mm, 30 mm. It is mostly found in construction industry for erecting buildings, roads along with water filtration and sewage treatment processes.

Aggregates stand for the static materials which are blended in fixed ratios with a Binding Material to form concrete.

The aggregates can be applied as fillers or volume increasing components as well as liable for maintaining strength , solidity and longevity of the concrete.

Qualities of Aggregates

The most vital properties of aggregate are given below :-

1. It should be chemically inert that means they should not respond to cement or any other aggregate or admixture.
2. It should contain adequate rigidity to get rid of scratching and erosion in the hardened state.
3. It should contain enough toughness to tolerate impact and vibratory loads.
4. It should be sufficiently strong to withstand compressive and normal tensile loads in ordinary mixture.
5. There should be no impurities, inorganic or organic in nature, which may provide significant impact on its quality.
6. It should have the capability of developing an easily executable plastic mixture on amalgating with cement and water.

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Categorization of aggregate

Based on the grain size, origin and volume-weight, the aggregates are categorized as follows:

Types of aggregates on the basis of Grain Size

It is mostly recognized classification method, where there are two types of aggregates like fine and coarse.

(i) In the Fine Aggregates, the grain-size remains among 4.75 mm and  0.15 mm. Conversely, these go through from sieve having mesh size of 4.75 mm and are kept on a sieve of 0.15 mesh size.
Sand is considered as globally recognized natural Fine Aggregate.

(ii) Coarse Aggregates: These types of aggregates are kept on the sieve of mesh size 4.75 mm. Their upper size is normally around 7.5 mm. Gravels obtained from river bed are treated as the best coarse aggregates in the formation of Common Concrete.

Under these situations, if they are not accessible easily, appropriate rock types are crushed to the preferred particle sizes for forming coarse aggregates.

Types on the Basis of Density

Based on the weight per unit volume, there are three types of aggregates.

(i) Standard or Normal: These types of aggregates provide strength and weighting to the Concrete of around  2300 to 2500 kg/m3.

Gravels, Sand and Crushed stone are considered as Standard or Normal Aggregates.

(ii) High-Density Aggregates:  These types of Aggregates are utilized in standard proportions given in heavy weight concretes. Such concretes are mostly found as shields against X-rays and radiationsin atomic power plant.

Examples: Baryle – a natural mineral containing specific gravity of 4.3.

Concretes with such aggregate normally contain weight over 4000 kg/m3.

(iii) Light weight Aggregates. These comprise of natural and artificial materials with very low density in order that the consequential concrete has light weight, normally within a range of 350 to 750 kg/m3. They are particularly utilized in sound proofing and fire proofing constructions. They are also mostly suitable for developing light weight Pre-Cast concrete blocks.

For more details, go through the following construction article.
https://civilguides.com/aggregate-definition-aggregates-types/

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Published by
Rajib Dey
email : rajib_dey@aol.com
website : www.sketchup3dconstruction.com (construction related articles & news)